Freund's adjuvant produced severe
inflammation that augments development of
antibodies. Thus, mixed administration of
antigens with adjuvant was not required as long as
inflammation was induced in the hosts. Since macrophage activation for phagocytosis and antigen processing is the first step of antibody development,
inflammation-primed macrophage activation plays a major role in immune development. Therefore, macrophage activating factor should act as an adjuvant for immunization. The
inflammation-primed macrophage activation process is the major macrophage activating cascade that requires participation of serum
vitamin D3-binding
protein (DBP; human DBP is known as Gc
protein) and
glycosidases of B and T lymphocytes. Stepwise incubation of Gc
protein with immobilized
beta-galactosidase and
sialidase efficiently generated the most potent macrophage activating factor (designated
GcMAF) we have ever encountered. Administration of
GcMAF (20 or 100 pg/mouse) resulted in stimulation of the progenitor cells for extensive mitogenesis and activation of macrophages. Administration of
GcMAF (100 pg/mouse) along with immunization of mice with sheep red blood cells (SRBC) produced a large number of anti-SRBC antibody secreting splenic cells in 2-4 days. Thus,
GcMAF has a potent adjuvant activity for immunization. Although malignant tumours are poorly immunogenic, 4 days after
GcMAF-primed immunization of mice with heat-killed Ehrlich
ascites tumour cells, the
ascites tumour was no longer transplantable in these mice.